notmuch-emacs-mua: make --auto-daemon imply --create-frame

Before this change with --auto-daemon but without --create-frame
emacs server was started but no clients stay connected to it
(in both graphical and terminal displays).

Note that this changes how --client --auto-daemon works on
graphical display; New emacs frame is now created for the
message (and message-exit-actions hook appended).